Faulty Bolt Suspected in Japanese Tunnel Collapse that Killed Nine

YOSHIKAZU TSUNO/AFP/Getty Images(TOKYO) -- Authorities in Japan say an old rusty bolt may be the cause of a highway tunnel collapse on Sunday that killed nine people.

Investigators say the ceiling of the Sasago tunnel, about 50 miles west of Tokyo, is lined with concrete panels attached by metal rods secured by a bolt. When investigators got to the collapsed portion of the tunnel, a ceiling bolt was missing. Authorities say the bolt was quite old and rust may have caused it to come loose, triggering the collapse.

A fire broke out in the tunnel after the collapse, hampering rescue efforts. Five of the dead were found inside the charred remains of a van. A sixth person from the van managed to escape and walk out of the tunnel. Two elderly women, a man in his 50s and another man in his 70s were all found dead inside their crushed cars.

NEXCO, the private company that manages the Sasago tunnel, says there are a dozen others built just like it in Japan. The company has launched an emergency inspection of each one.